Bone marrow and peripheral blood expression of ID1 in human gastric carcinoma patients is a bona fide indicator of lymph node and peritoneal metastasis

Identification of metastasis-related genes by genomic and transcriptomic studies in murine melanoma

AIMS

We systematically characterized metastatic murine B16-F10 melanoma, a sub-line derived from murine melanoma B16-F1 cells.

MATERIALS AND METHODS

RNA-sequencing and network analyses (Ingenuity Pathway Analysis) were performed to identify novel potential metastasis mechanisms. Chromosomal aberrations were identified by multicolor fluorescence in situ hybridization (mFISH) using all 21 murine whole chromosome painting probes.

KEY FINDINGS

Numerous genes were overexpressed in B16-F10 cells, some of which have been already described as being metastasis-linked. Nr5a1/sf1, a known prognostic marker for adrenal tumors, was 177-fold upregulated in B16-F10 cells compared to B16-F1 cells. Hoxb8 was 75-fold upregulated, which was previously associated with gastric cancer progression and metastasis. Ptk7, which is linked with tumorigenesis and metastasis of esophageal squamous carcinoma, was 67-fold upregulated. B16-F10 cells acquired additional chromosomal aberrations compared to B16-F1 cells, including dic(4)(pter->qter:qter->pter), +dic(6;15), +der(10)t(10;?1;16).

SIGNIFICANCE

In addition to well-known metastatic genes, numerous novel genes and genomic aberrations were identified, which may serve as targets for treatment in the future. Transcriptomic and genetic analyses in B16-F10 cells unraveled a range of novel metastasis mechanisms, which may also have important implications for future treatment strategies.

Prognostic Impact of Immune-Related Gene Expression in Preoperative Peripheral Blood from Gastric Cancer Patients

BACKGROUND

Anti-PD-1 therapy has shown a promising clinical outcome in gastric cancer (GC). We evaluated the clinical significance of systemic immune-related gene expression in GC patients who underwent surgery.

METHODS

The correlation between the preoperative PD-1, PD-L1, and CD8 mRNA levels in peripheral blood (PB) and clinicopathological factors, including survival, in 372 GC patients was evaluated using quantitative RT-PCR. PD-1- and PD-L1-expressing cells were identified by flow cytometric analysis.

RESULTS

The PD-1, PD-L1, and CD8 mRNA levels in GC patients were significantly higher than those in normal controls, respectively (all P < 0.0001). The levels of each gene were positively correlated with those of the other two genes (all P < 0.0001). GC patients with low PD-1, high PD-L1, and low CD8 mRNA levels had significantly poorer overall survival (OS) than those with high PD-1, low PD-L1, and high CD8 mRNA levels, respectively (P < 0.01, P < 0.05, and P < 0.05, respectively). Multivariate analysis showed that low PD-1 and high PD-L1 mRNA levels were independent poor prognostic factors for OS (PD-1: HR 2.38, 95% CI 1.27-4.78, P < 0.01; PD-L1: HR 1.81, 95% CI 1.15-2.78, P < 0.05). PD-1 and PD-L1 expression occurred on T cells (> 90%) and T cells or monocytes (> 70%), respectively.

CONCLUSIONS

The PD-1, PD-L1, and CD8 mRNA levels in preoperative PB reflected the anti-tumour immune response, and the low PD-1 and high PD-L1 mRNA levels in PB were independent poor prognostic markers in GC patients who underwent surgery.

Recurrence of gastric cancer in patients who are disease-free for more than 5 years after primary resection

BACKGROUND

Late recurrence of gastric cancer is rare and there are few data on recurrence in patients who are disease free for >5 years after gastrectomy. The aim of this study was to evaluate the predictors and status of tumor recurrence among these patients.

METHODS

Clinicopathologic characteristics, patterns of recurrence, and postrecurrence survival were analyzed in patients who were diagnosed as disease free at 5 years postoperatively and thereafter experienced recurrence. Independent factors associated with the late recurrence were analyzed.

RESULTS

Among 1,573 patients who underwent curative surgery from June 1992 to December 2006, 348 patients had recurrence. Of them, 7.6% (n = 25) suffered from late recurrence after 5 years after gastrectomy. Among patients who were diagnosed as disease free at 5 years after surgery, it accounted for 2.8% (25/902). Cases with late recurrence were characterized by more aggressive clinicopathologic features than those without recurrence. The median time to recurrence was 88.8 months (range, 64.8-238.0); of the 25 patients, 18 (72.0%) had recurrence within 8 years after surgery. The most common pattern was peritoneal recurrence (n = 19; 76.0%). The estimated median survival after recurrence was 9.4 months. On multivariate analysis, pT4 classification was the only independent risk factor for late recurrence. There were 185 patients with pT4 tumor who had no recurrence at 5 years after surgery; 19 (10.3%) had late recurrence.

CONCLUSION

pT4 tumor was the only important predictor of late recurrence. Whether extended follow-up for T4 tumors affects survival needs to be demonstrated in more large-scale studies.

TGF-β1-induced expression of Id-1 is associated with tumor progression in gastric cancer

Transforming growth factor β1 (TGF-β1) and inhibitor of differentiation/DNA-binding 1 (Id-1) have been shown to be associated with aggressive metastatic behavior of cancer cells in many malignant tumors. However, their role in gastric cancer (GC) has not been established. In this study, we investigated the relationship between expression of Id-1 and TGF-β1 in GC as well as their association with GC progression. The immunohistochemical analysis of 71 human GC samples indicated that both Id-1 and TGF-β1 were markedly upregulated in tumor tissue compared with the adjacent tissue; in addition, a significant positive correlation was found between the expression levels of Id-1 and TGF-β1 by Pearson's correlation analysis. Furthermore, the investigation of the association of Id-1 and TGF-β1 with patient clinical characteristics revealed that Id-1 expression was significantly correlated with tumor differentiation, while TGF-β1 was associated with lymph node metastasis. The results were validated in vitro by using a GC cell line, AGS. The expression of Id-1 was upregulated at 24 and 48 h after the treatment with TGF-β1, whereas it did not affect the proliferation of cells. TGF-β1 also influenced the expression of N-cadherin and β-catenin. Our results suggested that Id-1 and TGF-β1 played important roles in the progression of GC, in which Id-1 might act as a downstream mediator of TGF-β1 signaling through a regulatory mechanism involving N-cadherin and β-catenin. The TGF-β1/Id-1 axis might serve as a future therapeutic target for GC.

ID proteins regulate diverse aspects of cancer progression and provide novel therapeutic opportunities

The inhibitor of differentiation (ID) proteins are helix-loop-helix transcriptional repressors with established roles in stem cell self-renewal, lineage commitment, and niche interactions. While deregulated expression of ID proteins in cancer was identified more than a decade ago, emerging evidence has revealed a central role for ID proteins in neoplastic progression of multiple tumor types that often mirrors their function in physiological stem and progenitor cells. ID proteins are required for the maintenance of cancer stem cells, self-renewal, and proliferation in a range of malignancies. Furthermore, ID proteins promote metastatic dissemination through their role in remodeling the tumor microenvironment and by promoting tumor-associated endothelial progenitor cell proliferation and mobilization. Here, we discuss the latest findings in this area and the clinical opportunities that they provide.

JWA suppresses tumor angiogenesis via Sp1-activated matrix metalloproteinase-2 and its prognostic significance in human gastric cancer

JWA, a multifunctional microtubule-binding protein, plays an important role in regulating tumor metastasis via inhibition of matrix metalloproteinase-2 (MMP-2). Recent investigations suggest that MMP-2 is an angiogenesis-associated molecule. In this study, we provide novel evidence that JWA inhibits tumor angiogenesis in gastric cancer (GC). In two independent retrospective GC cohorts, we found that the expression of JWA was downregulated and that of MMP-2 was upregulated in GC tissues compared with the same in normal gastric mucosa. For patients treated with surgery alone, a strong and independent negative prognostic value was shown for low JWA and high MMP-2 expressions separately, which was even stronger when combined (hazard ratio = 7.75, P < 0.001, in the training cohort; hazard ratio = 2.31, P < 0.001, in the validation cohort). Moreover, we found that loss of JWA expression was strongly correlated with increased GC angiogenesis. In vitro, JWA inhibited MMP-2 at both messenger RNA and protein levels by modulating Sp1 activity. Knockdown of endogenous JWA resulted in enhanced human umbilical vein endothelial cell tube formation and MMP-2 expression. Furthermore, JWA was found to inhibit Sp1 activity via an ubiquitin-proteasome-dependent mechanism and to downregulate the expression of the proangiogenic MMP-2. Our findings imply that JWA and MMP-2 may serve as promising prognostic markers in resectable GC, with JWA as a useful biomarker of angiogenesis in GC and a potential therapeutic target by MMP-2 modulation.

Gene expression of bone morphogenic protein 8B in the primary site, peripheral blood and bone marrow of patients with gastric cancer

The prognosis for individuals that are diagnosed with gastric cancer remains poor due to the high frequency of metastatic disease. In response to tumor-derived secreted factors, the bone marrow generates a suitable microenvironment for the development of metastasis. However, it is largely unknown whether secreted factors in bone marrow associated with metastatic disease of patients with gastric cancer are present. Secreted factors from the bone marrow of patients with metastatic gastric cancer were identified using a DNA microarray analysis and the mRNA expression levels were investigated in 355 bone marrow, 295 peripheral blood and 144 primary site samples using quantitative PCR (qPCR). Using DNA microarray analysis, the present study identified bone morphogenetic protein 8B (BMP8B) as a secreted signaling molecule in the bone marrow that was associated with the metastatic disease of human gastric cancer. The expression levels of BMP8B in the bone marrow of 355 gastric cancer patients were increased with metastatic disease. A significant correlation was demonstrated between BMP8B mRNA expression in the bone marrow and in the peripheral blood. High BMP8B expression in the bone marrow was associated with the diffuse type of gastric cancer (P=0.009), lymph node metastasis (P=0.009), liver metastasis (P=0.044) and peritoneal dissemination (P<0.001). In the primary site, a multivariate analysis revealed BMP8B mRNA expression as one of the independent prognostic factors of gastric cancer [hazard ratio (HR), 2.066; 95% CI, 1.132–3.772]. This study suggests that BMP8B, a previously unknown secreted factor in cancer progression, has the potential to be used as a prognostic biomarker. The present study may provide insight into a new mechanism that underlies the dissemination of gastric cancer cells.

A prospective evaluation of the utility of 2-deoxy-2-[(18) F]fluoro-D-glucose positron emission tomography and computed tomography in staging locally advanced gastric cancer

BACKGROUND

The aim of this study was to examine prospectively the utility of adding preoperative [(18) F]fluorodeoxyglucose positron emission tomography (FDG-PET)/computed tomography (CT) to routine CT, endoscopic ultrasound (EUS), and laparoscopic staging of localized gastric cancer.

METHODS

Patients with locally advanced gastric/gastroesophageal cancer were screened for 2 institutional review board-approved Memorial Sloan-Kettering Cancer Center neoadjuvant chemotherapy protocols. Locally advanced disease was defined as T3 or T4, or lymph node-positive, based on EUS and high-resolution CT scan. All patients underwent both standard FDG-PET/CT and laparoscopy with cytological examination of washings. The sensitivity and specificity of FDG-PET/CT for the identification of metastatic disease not seen on CT was determined. An economic model using Medicare/Medicaid reimbursement charges was developed to assess the cost-effectiveness of these interventions.

RESULTS

A total of 113 patients were enrolled from 2003 to 2010. All patients were assessed as having locally advanced disease by CT/EUS. FDG uptake in the primary tumor was associated with male sex, proximal tumors, and nondiffuse Lauren's subtype. 31 (27%) patients had occult metastatic disease detected by PET/CT (n = 11, 10%) and/or laparoscopy (n = 21, 19%), with a single overlap. Economic modeling suggests that the addition of FDG-PET/CT to the standard staging evaluation of patients with locally advanced gastric cancer resulted in an estimated cost savings of ∼US $13,000 per patient.

CONCLUSIONS

FDG-PET/CT identifies occult metastatic lesions in approximately 10% of patients with locally advanced gastric cancer. Because of reduced morbidity from fewer futile surgeries and lower patient care costs, PET/CT should be considered as a component of the standard staging algorithm for localized gastric cancer.

Id-1 and the p65 subunit of NF-κB promote migration of nasopharyngeal carcinoma cells and are correlated with poor prognosis

Inhibitor of differentiation (Id)-1 and nuclear factor-kappa B (NF-κB) have been detected in many malignant tumors, and their presence has been correlated with the metastatic potential of these tumors. This study was undertaken to investigate the prognostic significance of the expression of Id-1 and the p65 subunit of NF-κB (NF-κB/p65) and the proteins' roles in the invasion process of nasopharyngeal carcinoma (NPC) cells. The messenger RNA (mRNA) and protein levels of Id-1 and NF-κB/p65 in normal nasopharyngeal epithelial cells and NPC cell lines were examined using reverse transcription-PCR and western blot analysis, whereas the mRNA and protein levels of Id-1 and NF-κB/p65 in clinical NPC specimens were determined by reverse transcription-PCR and immunohistochemistry. Short hairpin RNA (shRNA) was used to silence Id-1 and NF-κB/p65 to allow for the examination of matrix metalloproteinase (MMP)-9 expression and migratory capacity changes in CNE-2 cells. Multivariate Cox analysis revealed that elevated Id-1 expression was a significant independent predictor of the 5 year overall survival rate (hazards ratio = 16.720, P = 0.005). Furthermore, elevated expression of both Id-1 and NF-κB/p65 was associated with poor clinical survival (P = 0.049). Targeting Id-1 and NF-κB/p65 mRNA with shRNA in CNE-2 cells inhibited MMP-9 expression and decreased the migratory capacity of CNE-2 cells. In conclusion, Id-1 expression is a novel independent prognostic marker molecule that helps identify NPC patients with a poor prognosis. Additionally, combined analysis of Id-1 and NF-κB/p65 can be useful for identifying patients at risk for unfavorable clinical outcomes. Id-1 or/and NF-κB/p65 enhanced tumor cell migration, which is associated with the secretion of MMP-9.

Osteosarcoma is characterised by reduced expression of markers of osteoclastogenesis and antigen presentation compared with normal bone

Background:

Osteosarcoma (OS) is the most common primary bone tumour in children and adolescents. Patients who respond poorly to chemotherapy have a higher risk of metastatic disease and 5-year survival rates of only 10–20%. Therefore, identifying molecular targets that are specific for OS, or more specifically, metastatic OS, will be critical to the development of new treatment strategies to improve patient outcomes.

Methods:

We performed a transcriptomic analysis of chemo-naive OS biopsies and non-malignant bone biopsies to identify differentially expressed genes specific to OS, which could provide insight into OS biology and chemoresistance.

Results:

Statistical analysis of the OS transcriptomes found differential expression of several metallothionein family members, as well as deregulation of genes involved in antigen presentation. Tumours also exhibited significantly increased expression of ID1 and profound down-regulation of S100A8, highlighting their potential as therapeutic targets for OS. Finally, we found a significant correlation between OS and impaired osteoclastogenesis and antigen-presenting activity. The reduced osteoclastogenesis and antigen-presenting activity were more profound in the chemoresistant OS samples.

Conclusion:

Our results indicate that OS displays gene signatures consistent with decreased antigen-presenting activity, enhanced chemoresistance, and impaired osteoclastogenesis. Moreover, these alterations are more pronounced in chemoresistant OS tumour samples.

Different real-time PCR systems yield different gene expression values

Most polymerase chain reaction (PCR) systems employ pre-determined settings and proprietary master mixes that differ from one system to another. It is not known whether these differences may affect gene expression values. We compared two major real-time PCR technologies, from Life Technologies (formerly Applied Biosystems; ABI7500) and Roche Applied Science (LC480), using their default settings, proprietary reagents and other potential variables such as ramp rates and magnesium concentrations. We analyzed four genes (IL-8, COX2, ID-1 and CXCR2) in a human breast cancer cell line and found that two of them, though readily detected by ABI, were not detected using the Roche system. By altering some of the parameters and reagents used in the Roche protocol, we were able to detect expression of these two genes, but the level remained far below that detected by ABI, particularly for ID-1. When we tested three additional ID-1 primer pairs, two of these primer pairs yielded higher expression values in the LC system, yet still significantly lower than the values obtained in ABI. These results suggest critical differences in these two PCR systems, which could result in significant discrepancies in results reported by different laboratories.

The clinical significance of vimentin-expressing gastric cancer cells in bone marrow

BACKGROUND

Expression of the mesenchymal marker gene vimentin (VIM) in gastric cancer is associated with a more aggressive form of the disease and poor prognosis. Because epithelial mesenchymal transition (EMT) plays a critical role in the progression of gastric cancer, VIM expression was examined in the bone marrow (BM) of gastric cancer patients.

METHODS

BM samples from 437 gastric cancer patients were collected and analyzed by quantitative RT-PCR. Expression of VIM protein in the primary lesions of resected gastric cancers was evaluated using immunohistochemistry. Furthermore, induction of VIM expression by TGF-beta1 and hypoxia was evaluated in gastric cancer cells.

RESULTS

VIM mRNA expression increased concordantly with clinical staging and was significantly associated with tumor invasion and lymph node metastasis (P < .0001). Though cancer cells in the primary lesions did not stain with VIM antibody, some of the cells invading the intratumoral vessels were strongly positive for VIM, but were negative for E-cadherin. Hypoxic conditions and treatment with TGF-beta1 induced VIM expression and repressed E-cadherin in gastric cancer cells, coupled with an alteration of cellular morphology.

CONCLUSIONS

We found that gastric cancer cells undergo EMT in BM to survive and metastasize. These findings suggest that isolated tumor cells have the potential to undergo EMT, which could increase the malignancy of gastric cancer.